Millions of people now take herbal products and other "dietary supplements." The Physicians' Desk Reference has published a PDR for Herbal Medicines listing their ingredients and indications, and the Drug Topics Red Book lists their prices.

Creatine, a natural amino acid derivative, and androstenedione, a testosterone precursor, are marketed as 'dietary supplements' in health food stores and are widely believed to enhance athletic performance. Both have been in the news recently because Mark McGwire, the baseball home-run record-setter, reportedly has said he takes both. Neither has been approved for any indication by the US Food and Drug Administration (FDA).

Chromium is marketed as a dietary supplement, usually containing 20-500 mcg of a chromium salt. It has been promoted for weight loss, muscle building, and for prevention and treatment of diabetes, among other claims. As a dietary supplement, chromium can be sold without proof of efficacy or safety.

Turmeric is a spice derived from the Curcuma longa plant. Dietary supplements and foods containing turmeric are widely promoted for relief of pain and to improve joint mobility, immunity, digestion, cardiovascular health, depression, anxiety, memory, and cognition.

Omega-3 (n-3) polyunsaturated fatty acids (PUFAs), mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are essential human nutrients. The main dietary source of PUFAs is fatty fish such as salmon, but small amounts may be converted from α-linolenic acid in nuts, seeds, and plant oils such as canola or flaxseed oil. An increased intake of these fatty acids has been shown to modify membrane function, inhibit thrombus formation, decrease inflammation, lower plasma triglycerides, and alter the electrical activity of the myocardium.

Many patients ask their physicians whether they should take vitamins. Since the last Medical Letter article on this subject, more data have become available on the benefits and risks of taking vitamin supplements.

Many patients ask their healthcare providers whether they should take vitamins. Since the last Medical Letter article on this subject, more data have become available on the benefits and risks of taking vitamins.

The FDA has approved 2 products containing omega-3 polyunsaturated fatty acids (PUFAs) for treatment of patients with severe hypertriglyceridemia (>500 mg/dL). Lovaza (formerly Omacor) is available by prescription. The second FDA-approved omega-3 product, Vascepa, which contains only EPA, will not be available until 2013. Many other brands of fish oil capsules are sold over the counter (OTC) as dietary supplements; the US Pharmacopeia has verified that some of these contain their labeled content, are soluble in the body, and contain neither heavy metals...

The results of a randomized, placebo-controlled trial of calcium and vitamin D supplements in more than 36,000 postmenopausal women, conducted as part of the Women’s Health Initiative (RD Jackson et al. N Engl J Med 2006; 354:669), have been misinterpreted by some patients to mean that they should stop taking such supplements.At the time of recruitment, the participants in this study had an average daily calcium intake of 1100-1200 mg. They were randomized to take either 1000 mg of calcium carbonate plus 400 IU of vitamin D3 or a placebo for an average of 7 years. Both groups were permitted...

The Medical Letter has received many inquiries about use of glucosamine, a basic constituent of articular cartilage glycosaminoglycans, for treatment of arthritis. A recently published book (The Arthritis Cure), several television news shows, and articles in The New York Times have suggested it may be effective for treatment of osteoarthritis. Glucosamine is sold as a 'dietary supplement' in the USA.